Transformer relay



July 5, 1932. ifs. E. AYL'SWRTH 'f TRNSFRMR RELAY Fld Dec. 2G, E331 Sheis-Shet o sn. R NM@ mw m MJ. m40@ A s wm MQ wm S Patented July 5, 1932 UNITED' STATES PATENT OFFICE SELDEN B. A YLSWORTH, OF WILKINSBURG, PENNSYLVANIA, ASSIGNOR TO THE UNION SWITCH & SIGNAL-COMPANY,`OF SWISSVALE, PENNSYLVANIA, A CORPORATON OF PENNSYLVANIA TRANSFORM'ER RELAY Application mea December 26,1931. serial No.' 583,277.` i

My invention relates to electrical devices of the type known as transformer relays, and has for an object the provision of a device of this kind which will operate at high etliciency both as a transformer and as a relay.

I will describe one form of device embodying my invention, and willk then point out the novel features thereof in claims.

In the accompanying drawings, Fig. 1 is lo a view showing in side elevation one form of transformer relay embodying my invention. Fig. 2 is a sectionalview ,on the line Tl--II of Fig. 1, looking in the direction indicated by the arrows. Fig. 3 is a sectional view on f the line III-III of Fig. 1, and also looking in the direction indicated by the arrows. .Fig Il is a diagrammatic View showing one means for energizing an auxiliary winding X forming part of the device shown in the preceding views.

Similar reference characters refer to similar partsin each of the views.

Referring'frstto Figs. 1, 2, and 3, the device comprises a transformer core T, and a relay core R, disposed in parallel relation and separated by non-magnetizable spacers 5. The transformer core T is of the shell type, whereas the relay core R is E-shaped with its open end at the bottom.

n A primary winding? encloses the middle leg of each core T and R, and a secondary winding S also cncloses each of these middlelegs. As shown in the drawings, the secondary winding is located outside of the primary winding, but this specific 'arrangement is not material to my invention.

Coacting with the open end of the relay core R is an armature A. This armature is members are supported on a strap 13l whichy as here shown, is attached to the relay core R. In accordance with usual practice, when the armature A is attracted to the poles of the relay core R, front contact 10-11 is closed i and'bacl: contact 1,0-12 is open. When the armature is released so that it falls away from its poles, the back contact 10'-12` will close and the front contact 1011 will open.

The device as thus far described Vis not highly efucient, because when the relay armature A is open, it is difficult to cause enough ymagnetic flux to pass throughthe relay core to close this armature without highly saturatling the closed magnetic circuit of the transfrom a portion of the secondary winding S, the auxiliary winding being so connected that the voltage thus supplied thereto opposes the rvoltage induced in this winding by the primary winding P.

Sincethe transformer primary P andthe auxiliary winding X both enclose the middle Vleg of the relay core R, avoltage is induced in the auxiliary winding by transformer action when `the primary winding P becomes energized. This induced voltage is of low magnitude, particularly when the armature A is opened, since only a small amount kof the transformer flux passes through the relay core, but it is nevertheless appreciable, and it increases when the air gap in the relay core is reduced yby the closing of the armature. As stated hereinbefore, the voltage applied to the auxiliary winding by the secondary winding S Aopposes the voltageinduced in theauxiliary winding by transformer action. The net result is that the energy used by the relay is reduced to a minimum and yet enough pull is exerted to close the armature A. When the maximum tractive effort is required, that is, when the armature A is open, the energy used by the relay is greatest, because the voltage induced in the auxiliary winding is lowest at that time. When theV armature is closed, anda much smaller tractive effort is needed, the voltage induced in the auxiliary Winding becomes greater' and also more nearly 180o out of phase with the secondary voltage, thus lowering the resultant impressed voltage and the current taken by the auxiliary Winding. The rise in the impedance of the auxiliary Winding due to shortening the air gap when the armature closes, decreases still further the current taken by this Winding. The electrical losses are thus kept at a minimum, and just suiiicient energy is used to hold the armature closed and maintain adequate contact pressure.

If desired, a ferrule of electro-conductive material may be placed so as to enclose a portion of the middle leg of the relay core R, as indicated at 15 in Fig. 3, for the purpose of reducing the noise incident to the operation of the relay.

Although I have herein shown and described only one form of transformer relay embodying my invention, it is understood that various changes and modifications may be made therein Within the scope of the appended claims Without departing from the spirit and scope of my invention.

I-Iaving thus described my invention, What I claim is: A

l. A transformer relay comprising a shell Vtype transformer core and an E-shaped relay core, a primary and a secondary Winding each enclosing the middle leg of each core, an auxiliary Winding enclosing the middle leg of said relay core only, means for supplying said auxiliary Winding With a voltage Which opposes the Voltage induced therein by said primary Winding, and an armature coacting With the open end of said relay core.

2. A transformer relay comprising a closed transformer core and an open relay core, a primary and a secondary Winding each enclosing a portion of both of said cores, an auxiliary Winding enclosing a portion of said relay core but no part of said transformer core, means for supplying said auxiliary Winding With a voltage which opposes the voltage induced therein by said primary Winding, and an armature coacting with the open end of said relay core.

3. A transformer relay comprising a shell type transformer core and an E-shaped relay core, a primary and a secondary Winding each enclosing the middle leg of each core, an auxiliary Winding enclosing they middle leg of said relay core only, means for supplying said auxiliary Winding with voltage from said secondary Winding which opposes the voltage induced therein by said primary winding, and an arma-ture coacting with the open end of said relay core.

A transformer relay comprising a closed transformer core and an open relay core, a primary and a secondary Winding each en- 

